ext4: no need to truncate pagecache twice in collapse range

We're already calling truncate_pagecache() before we attempt to do any
actual job so there is not need to truncate pagecache once more using
truncate_setsize() after we're finished.

Remove truncate_setsize() and replace it just with i_size_write() note
that we're holding appropriate locks.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/extents.c

@@ -5474,7 +5474,7 @@ int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
 	}
 
 	new_size = i_size_read(inode) - len;
-	truncate_setsize(inode, new_size);
+	i_size_write(inode, new_size);
 	EXT4_I(inode)->i_disksize = new_size;
 
 	ext4_discard_preallocations(inode);